The disclosure relates to oil and gas drilling operations where after a hole is drilled a casing is positioned in the large hole in the ground. For various reasons, the oil companies fill the region between the outside of the casing and the inside of the hole (the annulus region) with cement.
In general, it is very undesirable to have gas perforations up through the annulus region which causes lost production of gas and further can be very harmful to the environment. It should be noted that repairing such gas vent flows through concrete is extremely expensive whereby the chamber region in the annulus portion of this cemented area must be identified and a hole must be drilled and perforated and cement is filled therein. Present analysis indicates that such an operation is very cost prohibitive for such a repair. Therefore, taking steps to remove such opportunities for gas to appear in the annulus region is extremely advantageous to any oil drilling operation.
Oil companies today are holding pressure on newly cased and cemented oil and gas wells. This has proven to be an effective procedure in preventing micro annulus gas release into the cement and out the casing vent. However, using the drilling rig BOP is costly and consumes valuable daylight hours as well as delays due to darkness.
Disclosed below is a clamp system that holds a primary seal in place. It allows surface applied pressure to be exerted on the cement in the annulus through the casing bowl vent outlet. Employing the concepts disclosed below, non-productive rig time is eliminated as the rig is free to move to a new location soon after plug down. Further the methods described below assist in preventing vent gas flows depending on cement blend. Further, installing casing slips with desired tension while cement is in solution where pressures and volumes are recorded allows the annulus to be pressurized so the cement bond is under pressure to minimize costly remedial treatments by preventing gas migration. Further, safety and environmental issues are minimized by the better formed annulus cement.